In plain words
In daily life, for man, enjoyment and sacrifice do not go together. The man of sacrifice does not go near enjoyment at all. The man of enjoyment does not think of sacrifice. In such conditions, how can one enjoy an enjoyment joined with sacrifice? This is what the Īśāvāsya Upaniṣad says: when we give up both, the Ahaṅkāra in action and the attachment in experience, there will be no difference at all between sacrifice and enjoyment. So whatever karmas we do that are not joined with Ahaṅkāra and attachment, these are enjoyments joined with sacrifice. In this Ahaṅkāra and sense of possession, selfishness and self-interest are void. All karmas free of selfishness and self-interest, without exception, are just enjoyment joined with sacrifice. So every human being, too, must perform karmas as his duty and give no room to the Ahaṅkāra that says, "This is the fruit of my doing." We must give no room to the thought, "It is the fruit of the karmas I did, so I alone must enjoy it." This alone is the Īśāvāsya, which taught the principle of the Ātma. It went on showing that the enjoyment enjoyed after sacrificing this kind of Ahaṅkāra and sense of possession is itself true yoga.
What is yoga? Yoga is the divine wealth gained and gathered together through many sādhanas. This is what the Bhagavad Gītā says: Yogakṣemaṃ vahāmy aham. He said, "I will look after your yoga and kṣema." When we look into yoga and kṣema with a worldly eye, we think it means asking after our welfare and news, our house and home, wife and children, and our circumstances. For this worldly inquiry, the name yoga does not hold its meaning. Born as a human being, to win through many sādhanas the divinity that is beyond the human, and the sacred state of having attained it, is called yoga. That is, to gain the divinity not yet gained is itself yoga. To make visible the divine principle that is beyond sight is itself yoga. The principle that is joined only with a divinity of its own kind, that the eye does not see, the ears do not hear, the mind does not sense, and that does not melt the heart, that dwells on the divine plane: to bring that into experience is itself yoga. To make manifest the principle that is unmanifest and deep is itself yoga. To protect that yoga, the divinity won through all such sādhanas, is itself kṣema.